﻿using System;
using UnityEngine;
using UnityEditor;
using Object = UnityEngine.Object;

[CustomEditor(typeof(Transform),true)]
public class TransformInspector : Editor {

    SerializedProperty mPos;
    SerializedProperty mRot;
    SerializedProperty mScale;
    
    void OnEnable ()
    {
        mPos = serializedObject.FindProperty("m_LocalPosition");
        mRot = serializedObject.FindProperty("m_LocalRotation");
        mScale = serializedObject.FindProperty("m_LocalScale");
    }

    public override void OnInspectorGUI()
    {
        EditorGUIUtility.labelWidth = 15;
        serializedObject.Update();
        DrawPosition();
        DrawRotation();
        DrawScale();
        serializedObject.ApplyModifiedProperties();
    }

    void DrawPosition()
    {
        GUILayout.BeginHorizontal();
        bool reset = GUILayout.Button("P", GUILayout.Width(20f));
        EditorGUILayout.PropertyField(mPos.FindPropertyRelative("x"));
        EditorGUILayout.PropertyField(mPos.FindPropertyRelative("y"));
        EditorGUILayout.PropertyField(mPos.FindPropertyRelative("z"));
        if (reset) mPos.vector3Value = Vector3.zero;
        GUILayout.EndHorizontal();
    }


#region Rotation is ugly as hell... since there is no native support for quaternion property drawing
	[Flags]
	enum Axes : int
	{
		None = 0,
		X = 1,
		Y = 2,
		Z = 4,
		All = 7,
	}

	Axes CheckDifference (Transform t, Vector3 original)
	{
		Vector3 next = t.localEulerAngles;

		Axes axes = Axes.None;

		if (Differs(next.x, original.x)) axes |= Axes.X;
		if (Differs(next.y, original.y)) axes |= Axes.Y;
		if (Differs(next.z, original.z)) axes |= Axes.Z;

		return axes;
	}

	Axes CheckDifference (SerializedProperty property)
	{
		Axes axes = Axes.None;

		if (property.hasMultipleDifferentValues)
		{
			Vector3 original = property.quaternionValue.eulerAngles;

			foreach (Object obj in serializedObject.targetObjects)
			{
				axes |= CheckDifference(obj as Transform, original);
				if (axes == Axes.All) break;
			}
		}
		return axes;
	}

	/// <summary>
	/// Draw an editable float field.
	/// </summary>
	/// <param name="hidden">Whether to replace the value with a dash</param>
	/// <param name="greyedOut">Whether the value should be greyed out or not</param>

	static bool FloatField (string name, ref float value, bool hidden, bool greyedOut, GUILayoutOption opt)
	{
		float newValue = value;
		GUI.changed = false;

		if (!hidden)
		{
			if (greyedOut)
			{
				GUI.color = new Color(0.7f, 0.7f, 0.7f);
				newValue = EditorGUILayout.FloatField(name, newValue, opt);
				GUI.color = Color.white;
			}
			else
			{
				newValue = EditorGUILayout.FloatField(name, newValue, opt);
			}
		}
		else if (greyedOut)
		{
			GUI.color = new Color(0.7f, 0.7f, 0.7f);
			float.TryParse(EditorGUILayout.TextField(name, "--", opt), out newValue);
			GUI.color = Color.white;
		}
		else
		{
			float.TryParse(EditorGUILayout.TextField(name, "--", opt), out newValue);
		}

		if (GUI.changed && Differs(newValue, value))
		{
			value = newValue;
			return true;
		}
		return false;
	}

	/// <summary>
	/// Because Mathf.Approximately is too sensitive.
	/// </summary>

	static bool Differs (float a, float b) { return Mathf.Abs(a - b) > 0.0001f; }

	void DrawRotation ()
	{
		GUILayout.BeginHorizontal();
		{
			bool reset = GUILayout.Button("R", GUILayout.Width(20f));

			Vector3 visible = (serializedObject.targetObject as Transform).localEulerAngles;

			visible.x = ReginaMath.WrapAngle(visible.x);
			visible.y = ReginaMath.WrapAngle(visible.y);
			visible.z = ReginaMath.WrapAngle(visible.z);

			Axes changed = CheckDifference(mRot);
			Axes altered = Axes.None;

			GUILayoutOption opt = GUILayout.MinWidth(30f);

			if (FloatField("X", ref visible.x, (changed & Axes.X) != 0, false, opt)) altered |= Axes.X;
			if (FloatField("Y", ref visible.y, (changed & Axes.Y) != 0, false, opt)) altered |= Axes.Y;
			if (FloatField("Z", ref visible.z, (changed & Axes.Z) != 0, false, opt)) altered |= Axes.Z;

			if (reset)
			{
				mRot.quaternionValue = Quaternion.identity;
			}
			else if (altered != Axes.None)
			{
				foreach (Object obj in serializedObject.targetObjects)
				{
					Transform t = obj as Transform;
					Vector3 v = t.localEulerAngles;

					if ((altered & Axes.X) != 0) v.x = visible.x;
					if ((altered & Axes.Y) != 0) v.y = visible.y;
					if ((altered & Axes.Z) != 0) v.z = visible.z;

					t.localEulerAngles = v;
				}
			}
		}
		GUILayout.EndHorizontal();
	}
#endregion

    void DrawScale()
    {
        GUILayout.BeginHorizontal();
        bool reset = GUILayout.Button("S", GUILayout.Width(20f));
        EditorGUILayout.PropertyField(mScale.FindPropertyRelative("x"));
        EditorGUILayout.PropertyField(mScale.FindPropertyRelative("y"));
        EditorGUILayout.PropertyField(mScale.FindPropertyRelative("z"));
        if (reset) mScale.vector3Value = Vector3.one;
        GUILayout.EndHorizontal();
    }
    
}
